Polymer-directed self-assembly synthesis of tin-titanium-manganese compounded oxides with enhanced activity and sulfur tolerance for NH3-SCR

Abstract

The majority of NH3-SCR catalysts including MnOx and TiO2-MnOx still exist inferior activity at high temperature, low selectivity, and poor sulfur resistance due to unbefitting redox and adsorption capacities. Novel tin-titanium-manganese compounded oxides catalysts with improved activity and sulfur tolerance are synthesized through a unique polymer-directed self-assembly method for the first time. The reducibility, NH3, and NOx adsorption ability of TiO2-MnOx catalyst are promoted by the incorporation of tin, which contributes to elevating the catalytic activity. More surface chemisorbed oxygen species are formed over Sn-TiO2-MnOx, which is conducive to the generation of NO2, thus shifting the reaction process towards fast NH3-SCR to improve the activity. Moreover, the introduction of Sn could effectively inhibit the electron transfer between SO2 and Mn to suppress the generation of manganese sulfate, thus protecting the active sites. This work develops an enhanced strategy to design an environmental-friendly catalyst with superior catalytic activity and SO2 resistance.